When enable vfio-pci mode for NIC driver on Juno board, the IRQ is failed to forward properly from host to guest, finally root caused this issue is related with kvmtool cannot re-enable INTx mode properly. So the basic working flow to reproduce this issue is as below: Host Guest ------------- -------------------- INTx mode MSI enable failed in NIC driver MSI disable in NIC driver Switch back to INTx mode --> kvmtool doesn't support So this patch is to support INTx mode re-enabling; 0001/0002 patches are only minor fixing up for eventfd releasing and remove useless FDs reservation for INTx. 0003 patch is the core patch for supporting INTx mode re-enabling, when kvmtool detects MSI is disabled it rollbacks to INTx mode. This patch set has been tested on Juno-r2 board. Leo Yan (3): vfio-pci: Release INTx's unmask eventfd properly vfio-pci: Remove useless FDs reservation in vfio_pci_enable_intx() vfio-pci: Re-enable INTx mode when disable MSI/MSIX include/kvm/vfio.h | 1 + vfio/pci.c | 61 +++++++++++++++++++++++++++++++++++++--------- 2 files changed, 50 insertions(+), 12 deletions(-) -- 2.19.1 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm